The flexible pipes for offshore use are often unbonded pipes. The term “unbonded” means in this text that at least two of the layers of the pipe are not bonded to each other. Often unbonded flexible pipes comprise an internal sheath which forms a barrier against the outflow of the fluid which is conveyed through the pipe, and one or more armouring layers on the outer side of the internal sheath (outer armouring layer(s)). The flexible pipe may comprise additional layers such as a carcass which is an inner armouring layer to prevent the collapse of the internal sheath. An outer sheath may be provided with the object of forming a barrier against the ingress of fluids from the pipe surroundings to the armouring layers. In practice the pipe will normally comprise at least two armouring layers, which are not bonded to each other directly or indirectly via other layers along the pipe. Thereby the pipe becomes bendable and sufficiently flexible to roll up for transportation.
Typical unbonded flexible pipes are e.g. disclosed in WO0161232A1, U.S. Pat. No. 6,123,114 and U.S. Pat. No. 6,085,799.
The above-mentioned type of flexible pipes is used, among other things, for off-shore as well as some on-shore applications for the transport of fluids and gases. Flexible pipes can e.g. be used for the transportation of fluids where very high or varying water pressure exists along the longitudinal axis of the pipe, such as riser pipes which extend from the seabed up to an installation on or near the surface of the sea, pipes for transportation of liquid and gases between installations, pipes which are located at great depths on the seabed, or between installations near the surface of the sea.
In traditional flexible pipes, the one or more armouring layers are most often in the form of helically wound steel wires e.g. shaped as profiles, where the individual layers may be wound at different winding angle relative to the pipe axis. Inner armouring layers are often made from folded interlocked steel strips, e.g  folded strips, such as disclosed in U.S. Pat. No. 6,415,825.
In order to avoid formation of undesired gabs between the helically wound wires of the armouring layer, and in particular armouring layer adjacent to a internal sheath, the armouring layer are formed from interlocked profiled wires. A number of prior art documents disclosing such armouring layers formed from interlocked profiled wires. U.S. Pat. No. 6,065,501 discloses an armouring layer formed from interlocked T profiled wires or formed from alternating T and U profiled wires interlocked into each other. U.S. Pat. No. 6,415,825 discloses an armouring layer formed from interlocked Z profiled wires. U.S. Pat. No. 6,354,333 discloses I or H profiled wires interlocked a U profiled wires. U.S. Pat. No. 6,235,793 disclosed an armouring layer formed from X profiled wirers interlocked by a U profiled wires.
The object of the invention is provide a flexible pipe with an alternative armouring layer, which is simple to produce and has the necessary strength for use as armouring layers, such as pressure armouring layer and carcass.
This object has been achieved by the invention as claimed.